<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>p3_CSS常用值</title>
    <style>
        h1{
            color:red;
            color: rgb(255,0,0);
            color: rgb(0,255,255);
            color: rgb(0,255,0);
            color: rgb(255,0,255);
            color: rgb(0,0,255);
            color: rgb(255,255,0);
            color: rgb(0,0,0);
            color: rgb(255,255,255);

            color: rgba(255,0,0,1);
            color: rgba(255,0,0,0.8);
            color: rgba(255,0,0,0.5);
            color: rgba(255,0,0,0.3);
            color: rgba(255,0,0,0.1);
            color: rgba(255,0,0,0);
        }

        .d1 {
            width: 50px;
            height: 100px;
            background-image: url("img/mr.png");
            background-size:50px 100px;
            background-color: cyan;
        }
        .d2 {
            width: 500px;
            height: 300px;
            background-image: url("img/mr.png");
            border: 5px solid red;
            background-repeat: no-repeat;
            background-position: 0 0;/*背景图默认位置在左上角*/
            background-position: 0 50px;
            background-position: -50px 0;
            background-position: 50px -50px;
            background-position: center center;
            background-position: center;
            background-position: 50% 50%;
            background-position: 100% 100%;
        }

        .d3{
            width: 500px;
            height: 300px;
            background-image: linear-gradient(rgba(255,0,0,0),#00F);
        }
    </style>
</head>
<body>
    <h1>测试颜色</h1>

    <div class="d1"></div>
    <div class="d2"></div>
    <div class="d3"></div>
</body>
</html>